The best scenario for slowing global warming by 2100 requires the world to triple or quadruple by 2050 its use of renewable energy and sources of energy that emit only low amounts of greenhouse gases.

The recommendation comes from the Intergovernmental Panel on Climate Change in its third and final report of its fifth assessment. The report, which was authored by hundreds of scientists, focuses on ways to mitigate climate change. The panel released a summary of the report April 13 in Berlin, a...